(A) Field of the Invention
The present invention relates to an endoscope arranged to be able to perform a three-dimensional measurement by utilizing Moire topography.
(B) Description of the Prior Art
In case Moire topography is performed, it is in general necessary to provide a lattice for both the illumination optical system and the observation optical system. When it is intended to make an ordinary topographic observation by using these same optical systems, such a lattice hinders the observation. Especially, in case of a small-sized optical instrument such as endoscope, it is practically impossible to detachably mount a lattice within the foremost end portion of the instrument, and thus the prior known endoscope have the drawback that, for performing a Moire topography and an ordinary endoscopic observation, two separate endoscopic instruments (each being designed for a different specific purpose) have to be used. Also, there has been placed on the market an endoscopic instrument in which the lattice for observation optical system is omitted because the image of an object is scanned by using a photomultiplier. In such an instrument, it has been impossible to house a photomultiplier within the small space at the foremost end portion of the instrument because the size thereof is too large.